OBJECTIVE To investigate optimal beam quality for chest flat panel detector (FPD) system by semi-quantitatively assessment using a realistic lung phantom. MATERIALS AND METHODS Chest FPD radiographs were obtained on a realistic lung phantom with simulated lung opacities using various X-ray tube voltage levels (90-140 kV) with/without copper filter. Entrance skin dose was set to maintain identical for all images (0.1 mGy). Three chest radiologists unaware of the exposure settings independently evaluated the image quality of each simulated opacity and normal structure using a 5-point scale (+ 2: clearly superior to the standard; + 1: slightly superior to the standard; 0: equal to the standard; - 1: slightly inferior to the standard; - 2: clearly inferior to the standard). The traditional FPD image obtained at a tube voltage of 120 kV was used as the standard. The scores of image quality were statistically compared using the Wilcoxon rank test with Bonferroni correction. RESULTS FPD images using 90-kV shot with copper filter were superior to the traditional 120-kV shot without filter with respect to the visibility of vertebra, pulmonary vessels, and nodules overlapping diaphragm and heart (p < 0.05). There was no significant difference with respect to the visibility of all other simulated lung opacities (lung nodules except for overlying diaphragm/heart and honeycomb opacity) between each tube voltage level with/without copper filter and the traditional 120-kV shot without filter. CONCLUSION Image quality of FPD images using 90 kV with copper filtration is superior to that using standard tube voltage when dose is identical. KEY POINTS • FPD image quality using 90 kV with filter is superior to that using traditional beam. • Ninety-kilovolt shot with copper filter may be suitable for chest FPD image. • Clinical study dealing with chest FPD beam optimization would be warranted.

中文翻译：

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胸部平板探测器系统的最佳光束质量：真实的幻像研究。

目的通过使用真实的肺部幻象进行半定量评估，来研究胸部平板探测器（FPD）系统的最佳光束质量。材料与方法使用各种X射线管电压水平（90-140 kV），带/不带铜滤光片，在具有模拟肺部混浊的逼真的肺部体模上获得胸部FPD射线照片。入口皮肤剂量设置为对于所有图像均保持相同（0.1 mGy）。三名不知道曝光设置的胸部放射科医生使用5分制对每个模拟的不透明性和正常结构的图像质量进行了独立评估（+ 2：明显优于标准； +1：略高于标准； 0：等于标准标准；-1：略低于标准；-2：明显低于标准）。以在120 kV的管电压下获得的传统FPD图像作为标准。使用Wilcoxon等级检验和Bonferroni校正对图像质量得分进行统计比较。结果在椎骨，肺血管和结节与心脏重叠的结节的可见性方面，使用90kV铜箔滤镜拍摄的FPD图像优于传统的120kV铜箔滤镜拍摄的图像。在有/无铜过滤器的每个管电压水平与没有过滤器的传统120 kV照度之间，所有其他模拟肺部不透明性（除了覆盖隔膜/心脏和蜂窝的不透明性以外的肺结节）的可见性没有显着差异。结论当剂量相同时，使用90 kV铜过滤的FPD图像的图像质量优于使用标准管电压的FPD图像。要点•使用90 kV滤光片的FPD图像质量优于使用传统光束的FPD图像质量。•用铜滤镜拍摄的九十伏特电压可能适合胸部FPD图像。•必须进行有关胸部FPD束优化的临床研究。